1. Field of the Invention
The present invention relates to a paper supply apparatus which is used in a copying machine, printer, facsimile or the like, and to an image forming apparatus equipped with the paper supply apparatus.
2. Description of the Related Art
A paper supply apparatus such as a paper supply cassette apparatus comprises a paper accommodating unit configured to accommodate stacked paper sheets and to be drawn out from the main body of an image forming apparatus (see, for example, Japanese Patent Application Publication No. H10-101237). The paper supply cassette apparatus comprises an outer plate, which is observed outside the main body, and a handle between this outer plate and the paper accommodating unit. The handle is configured to engage the cassette with the main body. When the user pulls the cassette toward the outer side of the main body, the paper accommodating unit is opened to the outside. On the other hand, when the cassette is pushed toward the inside of the main body, then the paper accommodating unit is closed.
The paper in the paper accommodating unit is supplied out toward the interior of the main body at a prescribed conveyance pressure. Therefore, the cassette has to be accurately installed on the main body. For example, a hook locking mechanism provided on the upper end of the handle may work for accurate installation of the cassette on the main body. When the upper end of the handle with the hook locking mechanism is moved toward the paper accommodating unit, the engagement between the hook locking mechanism and the main body is released so that the user may draw the cassette out from the main body.
The hook locking mechanism, which is required for accurate installation of the cassette, may prevent the user from intuitively operating the cassette such as just simply drawing out it because the user has to insert his/her finger tips into the lower end of the outer plate, and then grip the handle with his/her index finger to unlock the hook locking mechanism with pressing the outer plate with his/her thumb in order to draw out the cassette when he/she tries to open the paper accommodating unit. In addition, an insufficient force onto the outer plate, an insufficient gripping force to the handle or a case that user grips the handle at a wrong position far from the prescribed adequate position may result in a failure in unlocking the hook locking mechanism.